The Solar Impulse takes flight

In our April issue, we carried a terrific feature by Bruno Giussani on an ambitious plan to fly around the world on a solar-powered plane. Bertrand Piccard and André Borschberg plan to circumnavigate the Earth using only solar energy.

Their prototype -- registration code HB-SIA -- was unveiled last June at a hangar in a disused Swiss Air Force base in Dübendorf, near Zurich. Then, last December, the 1,600kg plane underwent a successful test flight.

Today there's an important update from Bruno: Solar Impulse took off this morning from Payerne airfield, in western Switzerland, on its successful maiden flight. The aircraft climbed to 1,200m, and landed after 87 minutes of turns and maneuvres.

"Test pilot Markus Scherdel used the opportunity to test various manoeuvres (turns, simulating the approach phase) and to verify the plane's controllability, which so far had only been simulated with computers," Bruno reports.

After landing safely, André Borschberg, CEO and co-founder of the project, said: "This first mission was the most risky phase of the entire project. Eighty-seven minutes of intense emotion, after seven years of research, testing and perseverance. Never has an airplane as large and light ever flown before! The success of this first flight allows us to envisage the further program with greater serenity."

It's a great achievement: although it weighs as much as the average car (1,600kg), the Solar Impulse has the wingspan of an Airbus A340 (63.4 metres), and in flight should consume about the same amount of energy as a Vespa scooter.

You can watch a video of today's below. It's compelling. And then you can read (or re-read) Bruno's piece.